An analog to digital converter (ADC) is an electronic device that converts a continuous signal (i.e., an analog signal) into a discrete time (digital) representation. Analog to digital converters may convert input analog voltages or currents into digital values. The digital values may be proportional to the magnitude of the voltage level of the input analog signal. The resolution of the converter indicates the number of discrete values it can produce over the range of analog values. When the values are stored electronically in a binary form, the resolution is expressed in bits.
A successive approximation type ADC samples an analog voltage input, and applies a binary search to converge on a digital value that best represents the analog voltage input. In a successive approximation ADC, control circuitry provides an approximation value to a digital to analog converter (DAC). The DAC generates an analog voltage from the approximation value, and a comparator compares the sampled and held analog voltage input with the voltage generated by the DAC. The control circuitry successively determines the value of each bit of a digital output value based on the compared voltages.